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Author(s)
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Mihai, R E (Bucharest, IFIN-HH) ; Mare, A S (Bucharest, IFIN-HH ; Bucharest U.) ; Mărginean, N (Bucharest, IFIN-HH) ; Petrovici, A (Bucharest, IFIN-HH ; Bucharest U.) ; Andrei, O (Bucharest, IFIN-HH) ; Boromiza, M (Bucharest, IFIN-HH) ; Bucurescu, D (Bucharest, IFIN-HH) ; Căta-Danil, G (Bucharest, IFIN-HH) ; Clisu, C (Bucharest, IFIN-HH) ; Costache, C (Bucharest, IFIN-HH) ; Dinescu, I (Bucharest, IFIN-HH) ; Filipescu, D (Bucharest, IFIN-HH) ; Florea, N (Bucharest, IFIN-HH) ; Gheorghe, I (Bucharest, IFIN-HH) ; Ionescu, A (Bucharest, IFIN-HH) ; Lică, R (Bucharest, IFIN-HH ; CERN) ; Mărginean, R (Bucharest, IFIN-HH) ; Mihai, C (Bucharest, IFIN-HH) ; Mitu, A (Bucharest, IFIN-HH) ; Negret, A (Bucharest, IFIN-HH) ; Niţă, C R (Bucharest, IFIN-HH) ; Olăcel, A (Bucharest, IFIN-HH) ; Oprea, A (Bucharest, IFIN-HH) ; Pascu, S (Bucharest, IFIN-HH ; CERN) ; Şerban, A (Bucharest, IFIN-HH) ; Sotty, C (Bucharest, IFIN-HH) ; Stan, L (Bucharest, IFIN-HH) ; Şuvăilă, R (Bucharest, IFIN-HH) ; Toma, S (Bucharest, IFIN-HH) ; Turturică, A (Bucharest, IFIN-HH) ; Ujeniuc, S (Bucharest, IFIN-HH) ; Ur, C A (Bucharest, IFIN-HH) |
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Abstract
| The assignment of the first $2^+$ state in $^{62}$Ga has long been debated, due to its implications in triplet energy difference systematics in this mass region. An experiment has been performed at the IFIN-HH 9-MV Tandem accelerator using the ROSPHERE array in a mixed configuration of LaBr$_3$(Ce) and HPGe detectors, as well as an additional array of liquid scintillator neutron detectors. Excited states in $^{62}$Ga were populated through a $2n$ fusion-evaporation channel and an anisotropy ratio was obtained from neutron-filtered HPGe statistics of transitions observed at different angles. A $2^+$ state has been confirmed at an excitation energy of 978.1(1) keV. Theoretically, the interplay between isospin-symmetry breaking and shape-coexistence effects in the $A = 62$ isovector triplet is self-consistently treated within the beyond-mean-field complex excited Vampir variational model with symmetry projection before variation using an effective interaction obtained from a G matrix based on the charge-dependent Bonn CD potential adding the Coulomb interaction between the valence protons. Results are presented on Coulomb energy differences, mirror energy differences, triplet energy differences, and the superallowed Fermi $\beta$ decay of the ground state of $^{62}$Ge and $^{62}$Ga. |